Emergency handling of catalytic device accidents

Fire, power fluctuations, poor fluidization, serious equipment failure

Let’s talk about the accident involving the main fan. My unit is equipped with two main fans. When Fan No. 1 was in operation, oil leaked from the gearbox. It wouldn’t have been a problem normally, but below that area is the outlet pipeline of the main fan; the oil seeped into this pipeline, leading to a fire. Fortunately, it was discovered in time, so no major accident occurred. There have been quite a few fire incidents over the years, especially those related to the oil transfer lines under normal pressure. Therefore, to all producers: no accident is trivial; the key is to strengthen management and conduct more regular inspections.

Principles of management for acute poisoning: Acute poisoning caused by various factors often requires emergency treatment. If one understands some of the principles for treating acute poisoning, it is possible to provide timely and rapid care to patients with acute poisoning, which not only reduces the risk of complications but also helps to save their lives. Different poisons cause various symptoms of poisoning, and usually there are also specific methods for treatment. It is most common with poisons that enter the stomach; if poisons that have just entered the stomach can be vomited up as soon as possible, it is possible to **reduce the symptoms of poisoning**. Inducing vomiting immediately is a top priority. The human throat is sensitive to vomiting; gently touching the throat with fingers, cotton swabs, toothbrush handles, chopsticks, etc., can trigger nausea and vomiting ； Rinsing the mouth with warm soapy water can also cause vomiting ； Taking 100-200 milliliters of 0.25-0.5% zinc sulfate orally can also cause vomiting ； When conditions permit, 2–5 mg of dehydrated substance should be administered by subcutaneous injection, as it can induce central vomiting. Gastric lavage using a gastric tube is a good method for removing toxins from the stomach. In the household, consuming milk, soy milk, and egg whites can act as a antidote against poisoning caused by lysol and other strong acids and strong bases ； Drinking warm, strong tea serves as an antidote for mushroom poisoning as well as poisoning caused by drugs such as atropine and strychnine ； Oral administration of 2% soda water has a detoxifying effect on patients who have ingested organophosphorus pesticides. If the poison has entered the intestines, appropriate laxatives should be taken. Taking 50 ml of 50% magnesium sulfate orally or 30–50 ml of castor oil has a laxative effect, but lipid-based laxatives should not be used in cases of organophosphorus pesticide poisoning. When conditions permit, the use of specific antidotes is the ideal treatment method. Dithiopropyl alcohol is a detoxifier for heavy metals such as arsenic, mercury, antimony, bismuth, and gold. There are also some poisons for which antidotes can be used based on their pharmacological effects; for example, **in cases of poisoning, clonidine and Ritalin can be used. In treating acute poisoning, it is also necessary to strive to maintain the patient’s blood pressure and breathing, closely monitor changes in the patient’s heart rate and rhythm, and provide timely treatment based on the symptoms.

Analysis and Countermeasures for Hydrogen Sulfide Poisoning Incidents. Hydrogen sulfide is a highly hazardous asphyxiating gas, and fatal accidents resulting from hydrogen sulfide poisoning occur frequently in petrochemical enterprises. Therefore, it is particularly necessary to carry out proactive and careful preventive measures to avoid hydrogen sulfide poisoning. Next, let’s look at two cases of hydrogen sulfide poisoning incidents: 1. On August 7, 1999, a hydrogen sulfide pipeline in the hydrocracking unit of a factory leaked, and at 9:15, an employee collapsed after being exposed to the gas during a routine inspection. Upon discovering this, the team leader immediately put on a gas mask to carry out the rescue. During the rescue effort, the person wearing a gas mask that could not protect against hydrogen sulfide was also overcome by the fumes, resulting in a serious accident that claimed two lives. This accident was caused by the workers failing to take necessary preventive measures during their inspections, as well as the team leader wearing a gas mask incorrectly while attempting to provide rescue. 2. On January 21, 2000, the acidic water system in the refining section of a certain plant’s catalytic unit was shut down, and drainage operations were carried out on all relevant pipelines. As per the regulations, the valve on the feed line of the stripping tower should be closed first using the acid water pump, after which the outlet valve and the outlet drain valve of the acid water pump should be opened to discharge the liquid. However, the operator failed to close the valve on the feed line from the acid water pump to the stripping tower before opening the pump outlet valve and the drain valve to discharge the liquid, and no one was monitoring the discharge process. After the acidic water was discharged from the feed line, hydrogen sulfide gas at a pressure of 0.23 MPa and a concentration of 68% passed through the feed line from the drain valve of the acid water pump, quickly filling the entire pump room. At around 10:05 at that time, two female workers who were cleaning the pump room were immediately overcome by hydrogen sulfide gas and suffered from poisoning and asphyxiation. They were discovered around 10:10, and emergency measures were taken immediately. During these efforts, 7 more people suffered poisoning to varying degrees; 2 female workers died despite attempts to save them, while the remaining 7 were taken to the hospital for observation and treatment. Fortunately, no one else was in danger. The direct cause of the accident was that the operator on duty failed to discharge the acidic water into the pump room through the valve on the stripping tower pipeline during dehydration and condensate removal. This is a serious accident resulting from improper operation. These two accidents alone are undoubtedly a sufficient warning for those who work in areas with hydrogen sulfide-containing equipment. So, how can accidents causing injury or death be avoided when working in such areas? Measures to prevent hydrogen sulfide poisoning: 1. Personnel working in areas with hydrogen sulfide-containing equipment must receive education and training on hydrogen sulfide poisoning and first aid before starting work, and must pass an examination before being allowed to take up their duties. Through education and training, employees are made aware that hydrogen sulfide is a highly hazardous asphyxiating gas and a potent neurotoxin, thereby gaining a comprehensive understanding of its hazards, properties, and characteristics. Hydrogen sulfide is colorless and has a rotten egg smell. The human olfactory threshold for hydrogen sulfide is 0.012–0.03 mg/m3. Initially, the intensity of the hydrogen sulfide odor increases in proportion to the concentration, but once the concentration exceeds 100 mg/m3, the odor weakens as the concentration rises. At high concentrations, people cannot detect the presence of hydrogen sulfide due to rapid olfactory fatigue; therefore, it is not possible to determine the risk of poisoning based on the intensity of its odor. The maximum allowable concentration of hydrogen sulfide in the air is 10 mg/m3; appropriate respiratory protection must be worn when entering areas where this concentration is exceeded or may be exceeded. The higher the hydrogen sulfide concentration, the greater its toxicity to the human body. Higher concentrations of hydrogen sulfide (200–300 mg/m3) can cause tearing, stinging in the eyes, blurred vision, dizziness, headaches, and even loss of consciousness ； High concentrations of hydrogen sulfide (700–1000 mg/m3) can cause immediate symptoms in humans such as confusion, coma, muscle spasms, and incontinence ； When exposed to hydrogen sulfide at concentrations of 1000 mg/m3 or higher, a person collapses as if struck by electricity within seconds, breathing ceases immediately, and without prompt rescue, death can occur rapidly due to respiratory paralysis. All personnel working in, or who may need to work in, areas containing hydrogen sulfide should receive training on hydrogen sulfide safety knowledge once a year. Through training, employees gain a clear understanding of the hazards of hydrogen sulfide, thereby enhancing their awareness of self-protection. Through training and education, employees should also be taught the key points of first aid at accident scenes, and drills should be conducted. Carrying out rescue efforts at the accident scene promptly and correctly can often bring those who have been poisoned back to life, thereby creating conditions for further treatment. Key first-aid points: ① Before providing first aid, rescuers should wear appropriate protective equipment and be under the supervision of a designated person. ②Quickly move the patient to a place with fresh air. If breathing stops, artificial respiration should be performed immediately ； If the heartbeat stops, immediate chest compressions must be performed ； Patients with difficulty breathing are given oxygen therapy. 2. Employees are required to master the safety operation procedures for equipment as well as relevant management regulations, and detailed accident response plans must be developed. Regular drills should be organized to continuously improve employees’ skills in safe operation and their emergency response capabilities in handling accidents. During operations such as dehydration and coagulation removal, it is essential to first cut off all possible sources of hydrogen sulfide and install blind flanges to ensure absolute safety. Workers must wear appropriate gas masks when conducting inspections or working in areas with hydrogen sulfide. 3. Understand the distribution of hydrogen sulfide in the equipment area and the sources of risk related to hydrogen sulfide poisoning at this position. Fixed toxic and hazardous gas alarm devices and clear safety warning signs should be installed in areas where hydrogen sulfide may be present, to remind workers to take appropriate safety precautions; additional notices should also be provided if necessary. The set point and zero point of the alarm should be checked at least once a day; any abnormalities should be adjusted promptly. On-site personnel are not allowed to handle the alarm on their own ； If the probe is installed in an outdoor environment, it should be equipped with a rain cover ； Calibrate the sensors and monitoring systems regularly to ensure their accuracy, at least once per quarter. 4. Provide employees with appropriate and suitable protective equipment based on factors such as the oxygen content in the air at the production sites and work areas, as well as the concentration of hydrogen sulfide; employees are required to know how to use this equipment properly, maintain it correctly, and store it properly. ①Over 95% of hydrogen sulfide poisoning incidents are caused by inhalation exposure, and filtering gas masks, face masks, and isolated gas masks are commonly used to prevent such poisoning. When the hydrogen sulfide concentration in the air exceeds 30 mg/m3, or when the oxygen content in the air is below 18%, it is necessary to wear an oxygen respirator or an air respirator, or other types of isolated gas masks. Long-tube masks belong to the category of isolated gas masks; their length is determined so that the user does not experience a shortage of air supply, and it is generally 5–6 meters. When wearing a gas mask, facial hair should not come into contact with the sealing part of the mask; an appropriate filter canister must be used. Wearing a gas mask incorrectly often leads to serious injuries and deaths. ②Gas protection equipment must be regularly inspected and maintained to ensure it is clean and in good condition. The breathing device should be checked for proper condition before and after each use ； When not in use, it should be inspected and maintained at least once a month to ensure it remains fully ready for use at all times ； It must be placed in a designated location and kept by a designated person; it shall not be used without reason ； The storage location should be kept away from heat sources and flammable materials ； Be careful to protect it from moisture and sunlight ； Avoid contact with acids, alkalis, oils, and toxic substances ； The storage area should be clearly marked. ③Oxygen respirators have a complex structure; after use, it is necessary to have a professional inspect them and clean and disinfect the mask. The oxygen cylinder should be refilled when its remaining volume is below 85% of the total capacity. ④For those required to wear respiratory protection equipment in their daily work, a pulmonary function test should be conducted annually to determine whether they are capable of wearing such equipment. 5. Accelerate the innovation and upgrading of process technologies to achieve closed-system production, ensuring that the hydrogen sulfide concentration in the equipment area meets **health standards. The production process must be made airtight; the feeding ports of production equipment, rotating shafts, pipe connections, valves, and sewage drains all need to be completely sealed. For those feeding ports that cannot be fully sealed as well as for equipment that generates toxic substances, local ventilation systems and detoxification devices must be installed. The hydrogen sulfide emitted must be purified before it can be released into the atmosphere. 6. When entering equipment or containers containing hydrogen sulfide for work, it is necessary to cut off all sources of material in accordance with relevant safety regulations, thoroughly clean and purge the area, install blind flanges, and ensure that sampling analysis shows acceptable levels of hydrogen sulfide (less than 10 mg/m3). All safety measures must be implemented, and the permit for working inside the container must be obtained before entry is allowed, and this can only take place under the supervision of someone. Sampling and analysis must be carried out every hour or less; ventilation measures must be maintained throughout the operation to keep the oxygen level above 20%. 7. For sampling, measuring dimensions, dehydrating and removing sludge, plugging leaks for maintenance, and on-site rescue, appropriate gas masks should be used; at least two people should be present at the site simultaneously, and proper supervision measures must be in place. Guardians cannot leave the work site at will. 8. A dedicated person must regularly measure the hydrogen sulfide level in the working environment, and protective equipment should be worn during work. When the hydrogen sulfide concentration exceeds 10 mg/m3 due to changes in materials or operating conditions, the competent department shall work together with the workshop to analyze the reasons for this excess level, and take timely, scientific and effective protective measures to prevent poisoning of personnel. 9. Ventilation is an effective method for controlling the concentration of harmful gases in work areas. When there is a large release of hydrogen sulfide in the workplace, if no gas mask is worn, one should leave immediately; afterwards, while taking measures to reduce the concentration of harmful gases, a gas mask should be put on before proceeding with the work to seal the leak. 10. It is strictly prohibited to remove protective equipment before leaving the hazardous area (where hydrogen sulfide levels exceed 10 mg/m3) to prevent poisoning.

At 2:30 a.m. on March 2, our unit detected that the pilot slide valve had failed to lock in place; its position remained at the normal open setting, so an operator went to the site to manually adjust the slide valve； The instrumentation team was contacted; during repairs, it was found that there was no pressure in the slide valve power system and the oil pump would not start. Upon checking the power supply, it was determined that the motor of the slide valve oil pump had burned out. Fortunately, a spare motor was available, which was installed promptly. Testing was completed at 6 o’clock, and normal operation was restored.

Take some time to go through the device accident plan whenever you have a chance~~~~~~~~ Things that are generally important are usually included in it~~~~~~~~

I believe that accident emergency plans are developed based on incidents that have already occurred, and they have certain limitations. It’s better to listen here to everyone’s experiences regarding various accidents that have happened with different devices, in order to draw lessons from them and enhance our awareness of prevention.

Once, while I was at work, the level gauge in the settler stopped working; there was no indication of material level (the gauge showed 40%). Oil and gas entered the regenerator, causing it to emit yellow smoke and leading to a sudden rise in pressure. The relevant valve was shut down promptly, and the problem was resolved.

A few days ago, our small feeder was having frequent problems. During one inspection, it was found that the material could not be fed in, and the feeding pipe was hot to the touch. I spent a long time thinking about it back then; the heating of the feed pipe must have been caused by backflow from the regenerator. But how could it be reversed? Things returned to normal after increasing the air supply volume. Reason for analysis: Due to the overloading of the unit, the main air flow increased and the pressure in the regenerator rose; when small amounts of material were vented, it flowed back through the feeding line (due to leakage from the feeding valve). The air supply valve is still set at the opening level corresponding to the normal processing capacity before.

Yesterday at work, a supervisor came to check the pipeline; he said there was water in the steam and the temperature was only 120. Send the outside operator out to drain the water. As soon as I heard that, I immediately said it must be because the liquid level in the water tank of the waste heat boiler is too high. The chief operator is truly exceptional; as soon as he heard the instructions from the dispatcher, he went straight to release water. After a few minutes, the temperature rose to 300. I learned this from the HaiChuan forum as well; thank you

Principles for handling disruptions in demineralized water supply: Demineralized water is used for feeding boilers and steam drums, and in some systems it is also used for heat exchange with certain media. When the desalinated water supply is interrupted, the drum cannot operate properly due to a lack of water. 1. Activate feed self-protection for the reaction unit immediately ； Cut off the furnace, the first and second flue gases, and close the gas manual valve. When the steam pressure at 1.0 Mpa is too low, the three-vessel cycle is interrupted, the main air supply is cut off, and the dead bed is insulated. 2. The distillation unit shall handle the situation by shutting off the feed flow, and reduce the circulation rate of the oil paddles in the oil paddle heat exchanger; when there is no water level in the steam drum, this circulation can be suspended. 3. When demineralized water is used for cooling the main fan motor, switch to circulating water immediately. In case of high motor temperature, perform an emergency shutdown.

Handling of feed oil interruption in the unit (1) The reaction unit should first reduce the feed rate appropriately and lower the degree of reaction, while closely monitoring the drop in the liquid level in the feed mixing tank. At the same time, contact should be made with the feed oil storage area to restore supply. (2) If the liquid level indicator in the V-material mixing tank shows 0% scale, immediately stop feeding while maintaining the circulation of the crude oil. (3) Other units shall cooperate with the reaction unit to reduce the load, such as shutting off the feed to the reaction unit; all units shall make corresponding adjustments in response to this feed shutdown, but the distillation unit must ensure the circulation of the slurry and the liquid level at the bottom of the tower.

Handling of short-term interruption of feed oil in the unit: (1) The reaction unit should immediately increase the misting steam to maintain fluidization in the three reactors, control the pressure in the reaction system, and if necessary, use combustion oil to maintain the temperature of the regeneration bed and the oxygen content in the flue gas. (2) Pay attention to the load on the combustion furnace; reduce the flame intensity or turn it off. (3) The distillation unit maintains slurry circulation and controls the liquid level at the bottom of the distillation tower. (4) For other positions, control the temperature, pressure, and liquid level, keep the system running, and wait for feeding.

Prolonged interruption of feed oil in the unit: (1) The reaction section shall carry out the following actions in addition to those taken for short-term feed interruptions. ① Reduce the wind volume by one or two units, then increase it again, and use combustion oil to maintain the bed temperature of both regenerators at 550°C. ? ② The burner is turned off (only the pilot light remains). ③ Distillation performs a steam purging of the crude oil system. (2) Unit position: ① Maintain proper operation of the unit to ensure air supply to the regenerator. ② If necessary, contact the reaction unit to use a double-acting slide valve to control the regeneration pressure and close the inlet gate valve of the flue gas fan. (3) For other positions, corresponding actions should be taken by shutting off the feed in response to the situation; when the air compressor cannot operate due to reverse rotation, it can be shut down following the normal procedures and placed in standby mode. (4) Once the crude oil supply is restored, each station resumes production in the normal sequence.

Due to a power fluctuation, the main air one-way damping valve failed to operate, resulting in catalyst backflow. The personnel on duty at the main fan station took prompt action to prevent the accident from worsening.